Field of the Invention
The present invention relates to a solid state imaging device and an imaging system.
Description of the Related Art
Japanese Patent Application Laid-open No. 2012-010008 discloses a solid state imaging device that cancels noises due to a potential difference on ground wirings from a current source. The solid state imaging device of Japanese Patent Application Laid-open No. 2012-010008 has a holding capacitor that holds, at a predetermined potential, a gate potential of the current source connected to signal lines that read out signals from pixels.
In Japanese Patent Application Laid-open No. 2012-010008, however, a potential difference occurring on ground wirings in a pixel region is not taken into consideration. When a magnetic field around a solid state imaging device temporarily fluctuates and when ground wirings form a loop extending via the inside or the outside of the solid state imaging device, an induced electromotive force proportional to a temporal change amount of a magnetic flux penetrating the loop may occur on the ground wirings. Thus, a potential difference occurring on the ground wirings within the solid state imaging device including a pixel region may cause a noise. However, Japanese Patent Application Laid-open No. 2012-010008 neither discloses such a noise caused by a magnetic field fluctuation nor refers to any technology for reducing such noise.